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https://www.readbyqxmd.com/read/25105721/in-vivo-regional-ventilation-mapping-using-fluorinated-gas-mri-with-an-x-centric-fgre-method
#1
Alexei V Ouriadov, Matthew S Fox, Marcus J Couch, Tao Li, Iain K Ball, Mitchell S Albert
PURPOSE: Inert fluorinated gas lung MRI is a new and promising alternative to hyperpolarized gas lung MRI; it is less expensive and does not require expensive isotopes/polarizers. The thermally polarized nature of signal obtained from fluorinated gases makes it relatively easy to use for dynamic lung imaging and for obtaining lung ventilation maps. In this study, we propose that the sensitivity and resolution of fluorine-19 (19F) in vivo images can be improved using the x-centric pulse sequence, thereby achieving a short echo time/pulse repetition time...
August 2015: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/24238634/evaluation-of-cerebrovascular-reserve-using-xenon-enhanced-ct-scanning-in-patients-with-symptomatic-middle-cerebral-artery-stenosis
#2
Wenjie Cao, Xin Cheng, Haoxiong Li, Liang Wang, Xiaolong Zhang, Qiang Dong
Cerebrovascular reserve (CVR) is an important prognostic factor in patients with major cerebral arterial steno-occlusive disease. However, few studies have examined CVR in symptomatic intracranial stenosis without ipsilateral extracranial internal carotid artery stenosis. This study sought to evaluate CVR in patients with symptomatic middle cerebral artery (MCA) stenosis using xenon-enhanced computed tomography (Xe/CT) with acetazolamide (ACZ) challenge. Twelve patients with symptomatic MCA stenosis were recruited...
February 2014: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/24019158/xenon-enhanced-ct-assessment-of-cerebral-blood-flow-in-stroke-in-progress-patients-with-unilateral-internal-carotid-artery-or-middle-cerebral-artery-stenosis
#3
Zhen-Ni Guo, Ge Yang, Hong-Wei Zhou, Jing Wang, Jiang Wu, Yi Yang
Carotid or cerebral artery stenosis resulting in low perfusion is a major cause of ischemic stroke. Understanding the unique hemodynamic features in each patient undergoing a stroke-in-progress (SIP) and the correlation between progression and cerebral blood flow (CBF) status would help in the diagnosis and treatment of individual patients. We used xenon-enhanced CT (Xe-CT) to examine cerebral perfusion in patients with or without SIP (30 patients/group), recruited from October 2009 to October 2010. Only SIP patients with unilateral stenosis in the internal or middle cerebral artery were recruited...
December 2013: Neuroscience Bulletin
https://www.readbyqxmd.com/read/23649901/comparison-of-hyperpolarized-3-he-and-129-xe-mri-for-the-measurement-of-absolute-ventilated-lung-volume-in-rats
#4
COMPARATIVE STUDY
Matthew S Fox, Alexei Ouriadov, Giles E Santyr
PURPOSE: MRI using hyperpolarized noble gases, (3)He and (129)Xe, provides noninvasive assessments of lung structure and function. Previous work demonstrated that absolute ventilated lung volumes (aVLV) measured in rats using hyperpolarized (3)He agree well with micro-CT. METHODS: In this work, aVLV measurements were performed in rats using hyperpolarized (129)Xe MRI and compared with hyperpolarized (3)He measurements of aVLV under matched ventilation conditions...
March 2014: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/23476766/advanced-imaging-modalities-in-the-detection-of-cerebral-vasospasm
#5
Jena N Mills, Vivek Mehta, Jonathan Russin, Arun P Amar, Anandh Rajamohan, William J Mack
The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND)...
2013: Neurology Research International
https://www.readbyqxmd.com/read/23238360/worsening-respiratory-function-in-mechanically-ventilated-intensive-care-patients-feasibility-and-value-of-xenon-enhanced-dual-energy-ct
#6
Sandra Hoegl, Felix G Meinel, Sven F Thieme, Thorsten R C Johnson, Oliver Eickelberg, Bernhard Zwissler, Konstantin Nikolaou
OBJECTIVES: To evaluate the feasibility and incremental diagnostic value of xenon-enhanced dual-energy CT in mechanically ventilated intensive care patients with worsening respiratory function. METHODS: The study was performed in 13 mechanically ventilated patients with severe pulmonary conditions (acute respiratory distress syndrome (ARDS), n=5; status post lung transplantation, n=5; other, n=3) and declining respiratory function. CT scans were performed using a dual-source CT scanner at an expiratory xenon concentration of 30%...
March 2013: European Journal of Radiology
https://www.readbyqxmd.com/read/23231303/measurement-of-blood-flow-and-xenon-solubility-coefficient-in-the-human-liver-by-xenon-enhanced-computed-tomography
#7
Shigeru Sase, Hideaki Takahashi, Ryuta Shigefuku, Hiroki Ikeda, Minoru Kobayashi, Nobuyuki Matsumoto, Michihiro Suzuki
PURPOSE: The goal of this work was to develop a method of calculating blood flow and xenon solubility coefficient (λ) in the hepatic tissue by xenon-enhanced computed tomography (Xe-CT) and to demonstrate λ can be used as a measure of fat content in the human liver. METHODS: A new blood supply model is introduced which incorporates both arterial blood and portal venous blood which join and together flow into hepatic tissue. We applied Fick's law to the model. It was theoretically derived that the time course of xenon concentration in the inflow blood (the mixture of the arterial blood and the portal venous blood) can be approximated by a monoexponential function...
December 2012: Medical Physics
https://www.readbyqxmd.com/read/21990444/correlation-between-cerebral-blood-flow-and-oxygen-saturation-in-patients-with-subarachnoid-hemorrhage-and-traumatic-brain-injury
#8
Robert Shafer, Alice Brown, Christopher Taylor
The INVOS cerebral oximeter and portable xenon enhanced CT (Xe/CT) scan are two commonly used diagnostic devices in patients who have experienced neurologic insults such as traumatic brain injury and subarachnoid hemorrhage. While the INVOS device is a relatively inexpensive, non-invasive measure of cerebral blood oxygen saturation, Xe/CT is a more complex costly diagnostic test that is the current gold standard for assessing cerebral perfusion in patients in the neurosciences intensive care unit (NSI) at the University of New Mexico Hospital...
December 1, 2011: Journal of Neurointerventional Surgery
https://www.readbyqxmd.com/read/21700787/xenon-enhanced-cerebral-blood-flow-at-28-xenon-provides-uniquely-safe-access-to-quantitative-clinically-useful-cerebral-blood-flow-information-a-multicenter-study
#9
MULTICENTER STUDY
A P Carlson, A M Brown, E Zager, K Uchino, M P Marks, C Robertson, G P Sinson, A Marmarou, H Yonas
BACKGROUND AND PURPOSE: Xe-CT measures CBF and can be used to make clinical treatment decisions. Availability has been limited, in part due to safety concerns. Due to improvements in CT technology, the concentration of inhaled xenon gas has been decreased from 32% to 28%. To our knowledge, no data exist regarding the safety profile of this concentration. We sought to better determine the safety profile of this lower concentration through a multicenter evaluation of adverse events reported by all centers currently performing xenon/CT studies in the US...
August 2011: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/21538064/contralateral-cerebral-hemodynamic-changes-after-unilateral-direct-revascularization-in-patients-with-moyamoya-disease
#10
Yan Ma, Meng Li, Li Q Jiao, Hong Q Zhang, Feng Ling
Direct revascularization has been used successfully to prevent strokes by improving regional cerebral blood flow (rCBF) to the affected hemisphere faster in patients with moyamoya disease (MMD). Since most literatures have focused on the rCBF changes of operative hemisphere, we evaluated the hemodynamics of nonoperative side by xenon-enhanced computed tomography (Xe-CT) and acetazolamide challenge test in patients with MMD during a short time follow-up. Fifteen MMD patients with unilateral ischemic presentations who received direct revascularization on the symptomatic hemispheres with complete hemodynamic evaluations by Xe-CT and acetazolamide challenge test were enrolled...
July 2011: Neurosurgical Review
https://www.readbyqxmd.com/read/21274963/comparison-of-hyperpolarized-3-he-mri-with-xe-enhanced-computed-tomography-imaging-for-ventilation-mapping-of-rat-lung
#11
COMPARATIVE STUDY
Giles E Santyr, Marcus J Couch, Wilfred W Lam, Alexei Ouriadov, Maria Drangova, David G McCormack, David W Holdsworth
Lung ventilation was mapped in five healthy Brown Norway rats (210-377 g) using both hyperpolarized (3)He MRI and Xe-enhanced computed tomography (Xe-CT) under similar ventilator conditions. Whole-lung measurements of ventilation r obtained with (3)He MRI were not significantly different from those obtained from Xe-CT (p = 0.1875 by Wilcoxon matched pairs test). The ventilation parameter r is defined as the fraction of refreshed gas per unit volume per breath. Regional ventilation was also measured in four regions of the lung using both methods...
November 2011: NMR in Biomedicine
https://www.readbyqxmd.com/read/21073131/cerebral-blood-flow-and-metabolism-during-mild-hypothermia-in-patients-with-severe-traumatic-brain-injury
#12
Hiroyuki Masaoka
Cerebral blood flow (CBF) measurements during mild hypothermia therapy were made in 30 adult patients with severe head injuries (Glasgow Coma Scale score < or =18), by xenon enhanced computed tomography (Xe-CT). All patients but one underwent removal of hematomas and decompressive craniectomy. Immediately after surgery, hypothermia was induced by surface cooling, and a brain temperature of 32-35 degrees C was maintained for 3 days. During hypothermia therapy, CBF measurements by Xe-CT were made for all patients on post-injury days 1 to 4...
June 2010: Journal of Medical and Dental Sciences
https://www.readbyqxmd.com/read/20879605/subtraction-lung-image-for-evaluating-pulmonary-ventilation-in-xenon-enhanced-ct
#13
Shigeru Sase, Hideharu Nakano, Hiroshi Suzuki, Mitsuru Honda
PURPOSE: The goal of this work was to develop a method of transforming a xenon-enhanced CT (Xe-CT) image of the lung, so as to overlap well with its baseline CT image, and creating a subtraction image (enhanced image minus baseline image), and to demonstrate the possibility of evaluating pulmonary ventilation using the subtraction image. METHODS: Eight healthy men (37.1 +/- 10.1 yr) underwent Xe-CT lung studies. In protocol 1 for five subjects, 30% nonradioactive xenon (Xe) was inhaled for 2 min (washin) followed by air breathing for 4 min (washout)...
August 2010: Medical Physics
https://www.readbyqxmd.com/read/20700423/intracranial-vertebrobasilar-artery-dissection-associated-with-postpartum-angiopathy
#14
James S McKinney, Steven R Messé, Bryan A Pukenas, Sudhakar R Satti, John B Weigele, Robert W Hurst, Joshua M Levine, Scott E Kasner, Lauren H Sansing
Background. Cervicocephalic arterial dissection (CCAD) is rare in the postpartum period. To our knowledge this is the first reported case of postpartum angiopathy (PPA) presenting with ischemic stroke due to intracranial arterial dissection. Case. A 41-year-old woman presented with blurred vision, headache, and generalized seizures 5 days after delivering twins. She was treated with magnesium for eclampsia. MRI identified multiple posterior circulation infarcts. Angiography identified a complex dissection extending from both intradural vertebral arteries, through the basilar artery, and into both posterior cerebral arteries...
2010: Stroke Research and Treatment
https://www.readbyqxmd.com/read/18649466/determination-of-time-course-change-rate-for-arterial-xenon-using-the-time-course-of-tissue-xenon-concentration-in-xenon-enhanced-computed-tomography
#15
Shigeru Sase, Hideaki Takahashi, Hiroki Ikeda, Minoru Kobayashi, Nobuyuki Matsumoto, Michihiro Suzuki
In calculating tissue blood flow (TBF) according to the Fick principle, time-course information on arterial tracer concentration is indispensable and has a considerable influence on the accuracy of calculated TBF. In TBF measurement by xenon-enhanced computed tomography (Xe-CT), nonradioactive xenon gas is administered by inhalation as a tracer, and end-tidal xenon is used as a substitute for arterial xenon. There has been the assumption that the time-course change rate for end-tidal xenon concentration (Ke) and that for arterial xenon concentration (Ka) are substantially equal...
June 2008: Medical Physics
https://www.readbyqxmd.com/read/18641254/xenon-ventilation-ct-with-a-dual-energy-technique-of-dual-source-ct-initial-experience
#16
Eun Jin Chae, Joon Beom Seo, Hyun Woo Goo, Namkug Kim, Koun-Sik Song, Sang Do Lee, Soo-Jong Hong, Bernhard Krauss
Institutional review board approval and written informed consent were obtained. Although xenon (Xe) ventilation CT has been introduced as a potential method with which to depict regional ventilation, quantification of Xe enhancement has been limited by the variability of lung attenuation caused by different lung volumes between scans. The purpose of this study was to assess the feasibility of Xe ventilation CT with a dual-energy technique. Dual-energy CT was performed in 12 subjects after Xe inhalation. With use of a dual-energy technique, the Xe component could be extracted without any influence from lung volume...
August 2008: Radiology
https://www.readbyqxmd.com/read/18606518/imaging-of-lung-function-using-synchrotron-radiation-computed-tomography-what-s-new
#17
REVIEW
Sam Bayat, Liisa Porra, Heikki Suhonen, Tibor Janosi, Satu Strengell, Walid Habre, Ferenc Petak, Zoltan Hantos, Pekka Suortti, Anssi Sovijärvi
There is a growing interest in imaging techniques as non-invasive means of quantitatively measuring regional lung structure and function. Abnormalities in lung ventilation due to alterations in airway function such as those observed in asthma and COPD are highly heterogeneous, and experimental methods to study this heterogeneity are crucial for better understanding of disease mechanisms and drug targeting strategies. In severe obstructive diseases requiring mechanical ventilation, the optimal ventilatory strategy to achieve recruitment of poorly ventilated lung zones remains a matter of considerable debate...
December 2008: European Journal of Radiology
https://www.readbyqxmd.com/read/18250985/assessment-of-mean-transit-time-in-the-engrafted-lung-with-133xe-lung-ventilation-scintigraphy-improves-diagnosis-of-bronchiolitis-obliterans-syndrome-in-living-donor-lobar-lung-transplant-recipients
#18
COMPARATIVE STUDY
Takayoshi Shinya, Shuhei Sato, Katsuya Kato, Hideo Gobara, Shiro Akaki, Hiroshi Date, Susumu Kanazawa
OBJECTIVE: Staging of bronchiolitis obliterans syndrome (BOS) following lung transplantation is based on declines in forced expiratory volume in 1 s (FEV(1)). The aim of this study was to evaluate the usefulness of (133)Xe ventilation scintigraphy in the early detection of BOS following living-donor lobar lung transplantation (LDLLT), to compare (133)Xe washout imaging with computed tomography (CT) findings for early detection of BOS following LDLLT, and to evaluate (133)Xe washout imaging by quantitative analyses...
January 2008: Annals of Nuclear Medicine
https://www.readbyqxmd.com/read/17695380/enhancement-of-cerebral-blood-flow-using-systemic-hypertonic-saline-therapy-improves-outcome-in-patients-with-poor-grade-spontaneous-subarachnoid-hemorrhage
#19
Ming-Yuan Tseng, Pippa G Al-Rawi, Marek Czosnyka, Peter J Hutchinson, Hugh Richards, John D Pickard, Peter J Kirkpatrick
OBJECT: Systemic administration of 23.5% hypertonic saline enhances cerebral blood flow (CBF) in patients with poor-grade spontaneous subarachnoid hemorrhage (SAH). Whether the increment of change in CBF correlates with changes in autoregulation of CBF or outcome at discharge remains unknown. METHODS: Thirty-five patients with poor-grade spontaneous SAH received 2 ml/kg 23.5% hypertonic saline intravenously, and they underwent bedside transcranial Doppler (TCD) ultrasonography and intracranial pressure (ICP) monitoring...
August 2007: Journal of Neurosurgery
https://www.readbyqxmd.com/read/17690202/micro-ct-imaging-of-rat-lung-ventilation-using-continuous-image-acquisition-during-xenon-gas-contrast-enhancement
#20
Wilfred W Lam, David W Holdsworth, Louise Y Du, Maria Drangova, David G McCormack, Giles E Santyr
We measured ventilation (V) in seven anesthetized, mechanically ventilated, supine Wistar rats. Images of the whole lung were continuously acquired using a dynamic, flat-panel volumetric micro-computed tomography (micro-CT) scanner during ventilation with a xenon/oxygen (Xe-O(2)) gas mixture. Forty time-resolved volumes consisting of eighty 0.45-mm-thick slices (covering the entire lung) were acquired in 40 s, using a gantry rotation rate of one rotation per second. The animals were ventilated at a respiratory rate of 60 breaths/min, matching the gantry rotation rate, and imaged without suspending ventilation...
November 2007: Journal of Applied Physiology
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